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UNITED STATES PATENT OFFICE.

WM. F. SENIOR, OF NEW YORK, N. Y.

CONSTRUCTION 0F BOTTOMS FOR PIANOFORTES.

Specification of Letters Patent No. 4,282, dated November 21, 1845.

To all 'whom t may concern.'

Be it known Ythat I, WILLIAM F. SENIOR, of the city, county, and State of New York, have invented a new and Improved Mode of Making thel Bottoms for Pianofortes; and I do hereby declare that the following is a full and eXact description.

'Ihe nature of my invention consists in so arranging the planks and timbers, that the interior or middle layer shall form an arch springing from an abutment at each end on the underside coming together at the middle and joining the top, thus applying that principle in obtaining increased strength and power of resistance.

In order to enable others skilled in the art to make and use my invention, Iwill proceed to describe its construction, and operation.

Having selected suitable boards or plank I cut them in the lengths required (Figure l, a, a., a., a) and glue the edges of a sufIicient number together to form the necessary width planing these to a level and proper thickness. I then glue across each end of the boards thus prepared, two strips of plank (two inches thick and eight inches wide or thereabout) which forms part of the cross bracing and the abutmentof the arch, as seen at b, b, Figs. l, 2, 3. (F, l, C, (3,) are two smaller and thinner strips glued on the bottom board but in a diagonal direction across it. (Z, CZ, CZ, Figs. I, 2, 3, is a piece of plank about eight inches wide glued in a diagonal direction across the middle of the bottom, on this piece the two central ends of the pieces forming the arch rest. e, e, Figs. 2 and 3 is the arch plank forming the center of the bottom and is the main principle of this invention, this piece is made by gluing up several pieces of plank of about one inch stuff but in an angular direction so that the seams and grain will run as it were from corner to corner of the bottom and parallel with the strings of the instrument it is glued at each end firmly to the bottom planks a, a, a, a, and also to the cross pieces b, o, c, meeting in the middle it forms a butt joint resting on the cross piece, d, to which it is firmly attached. f f Figs. 2 and 3 are two small strips of plank glued on the arch piece e e, but diagonally across, immediately over and parallel to the strips shown at c c. Yothn ing now remains but to glue down the top doubling or Hoor g, (Figs. 2 and 3) which is made in all respects like the under floor a, a, a, ta) upon the tops of b, b, f, f, and upon a small part of the arch pieces e, e, near the center joint over CZ which is planed off to a faint level to receive it. The four small strips c, c, f, f, being glued about midway on either side of the arch e, e, prevents it from springing either up or down adding to the stifness of the arch and otherwise bracing it.

Fig. l represents the ground plan of the bottom with the manner o-f laying the cross pieces. Fig. 2 is a view of the front of the bottom when complete. Fig. 3, is a perspective View of the whole bottom, the t-op doubling not yet glued down but resting, on one edge showing the interior, with the manner of laying the arch.

Vhat I claim as my invention and desire to secure by Letters Patent, is-

The introduction of the arch in the middle of the bottom, whereby I am enabled to obtain great power of resisting the strain caused by the tension of the wire strings of the pianoforte, besides other advantages in improving the qualities of the instrument by keeping the case always in shape/so that it can not draw up or wind,7 as is invariably the result in the present mode of manufacture and consequently keeping the instrument in tune and order for a much longer period.

Vitnessed the siXth day of September in the year of our Lord one thousand eight hundred and forty-five.

WILLIAM F. SENIOR.

Witnesses:

JAS. PIRssoN, JULIAN Gr. DAvIEs. 

